|The "no signal" error should be fairly obvious. The monitor isn't receiving a video signal, that means the problem is with something within the computer. Could be the graphics card, motherboard, CPU, power supply, etc.|
The high speed fan indicates the CPU is overheating. The system is trying to lower the CPU temp by increasing the fan speed. You can't tell if it's overheating by "feel", you need to run a temp monitoring program or check the BIOS. Unfortunately, if you can't get a display, you can't check the temp.
You didn't list any specs but since your system has 10GB RAM, is running Win8, & has a monitor, it's most likely a relatively new desktop. Is it a custom build or store bought? What's the make/model? Did you do anything inside the case that may have brought this problem on? Did you do any cleaning, install RAM, mess with the CPU heatsink, etc?
You also posted in the wrong forum, this should be in hardware.